Sample size for the pilot study by the PASS2021 software [Power / Sample Size]

posted by dennis001 – Hong Kong, 2022-07-24 12:56 (726 d 09:53 ago) – Posting: # 23159
Views: 2,596

Dear colleagues,
We want to conduct a pilot study about the cardiovascular disease.
The aim of pilot study is to compare the postoperative levels of a biomarker between three treatment groups.
We try to estimate the sample size for the pilot study by the PASS2021 software.

PASS2021 software provide this routine presents rules of thumb for finding an appropriate sample size for a pilot study in which the outcome is a continuous measurement (postoperative levels of a biomarker in our study).
These results are for the total sample size of two-group studies in which the sample sizes of each group will be equal. Researcher should pick a sample size for the pilot study.
This procedure named Pilot Study Sample Size Rules of Thumb could generate reports which give the recommendations of statistical researchers as to the sample size of pilot studies. These rules of thumb for two groups can be adapted for single-group or multi-group studies by multiplying the recommended pilot study sample size by an appropriate adjustment factor (e.g., 0.5 for a study with only one group or 1.5 for a study with three groups, etc.).
The procedure based on the flat rules of thumb, which information provided in Machin et al. The results shown the sample size is no less than 10 for a study with only one group, no less than 20 for a study with two groups or no less than 30 for a study with three groups.
So, it seems that we could recruit 10 patients in each treatment group and a total of 30 patients for three groups in our pilot study?

We have uploaded the results estimated by PASS2021 Pilot Study Sample Size Rules of Thumb (see figure 1) [image]

However, could we conduct the Pilot Study based on the sample size? (eg. A total of 30 patients, 10 in each group, were included in our study.)
Any help would be much appreciated. Many thanks!

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